This application claims Paris Convention priority of DE 100 37 585.5 filed Aug. 2, 2000 the complete disclosure of which is hereby incorporated by reference.
The present invention concerns a canceling device for a blinker switch in motor vehicles which is disposed in the vicinity of a steering shaft and effects automatic canceling of the blinker switch from one of the two switched positions into the neutral central position, comprising a casing and a movable trigger finger which, in the switched positions, projects into the circular path of a cam connected to the steering shaft and is pretensioned towards the steering shaft, and comprising a switching piece which is disposed about an axis substantially parallel to the steering shaft and is provided with catch elements engaging in catch profiles and which cooperates with the trigger finger.
A canceling device of this type has been commercially available. When the blinker switch is actuated, the switching piece releases the trigger finger which moves radially inward towards the steering shaft and projects into the circular path of the cam connected to the steering shaft. Release of the trigger finger is effected by a helical pressure spring which is supported on one side on the trigger finger and on the other side on the casing of the canceling device.
The known canceling device functions well, however, there are two main disadvantages. Modern vehicles provide only little space in the region of the steering shaft which makes installation of the relatively large-volume canceling device difficult. Moreover, the known canceling device is relatively complicated to produce so that the associated cost cannot always be justified for modern motor vehicles.
It is therefore the underlying purpose of the present invention to further develop a canceling device of the above-mentioned type such that it is smaller and less expensive.
This object is achieved in a canceling device of the above-mentioned type in that it comprises a leaf spring, one side of which loads the trigger finger towards the steering shaft and the other side of which is supported on the casing.
In accordance with the invention, it has been determined that a reason for the relatively large size of the conventional canceling device is the manner in which the trigger finger is pretensioned. The known canceling device uses a helical pressure spring which requires a rather large guide to prevent bending. An intermediate piece, disposed between the spring and trigger finger, is also required.
The helical pressure spring, its guide and the intermediate piece require space which is no longer available. These components are no longer required in the inventive canceling device. Leaf springs typically exhibit an intrinsic stiffness such that the guide can be omitted and a leaf spring can load the trigger finger without an intermediate piece. The overall leaf spring provided in accordance with the invention is therefore much smaller than the conventional helical pressure spring. The parts required for guiding the conventional helical pressure spring and for connection to the trigger finger can be omitted in the inventive canceling device to reduce the direct production costs and the costs for assembly of the canceling device.
Further advantageous developments of the invention are given in the dependent claims.
An embodiment of the invention is described in detail below with reference to the accompanying drawing.